This application relates to a valve assembly for use with a pneumatic tool such as an air sander. Although valve assemblies of various types are known, such valve assemblies are normally relatively complex in construction, and are thus substantially expensive in cost and may not operate satisfactorily during use due to this complexity. Further, such valve assemblies are not normally particularly suitable for use in a pneumatic tool to provide the desired operation, and are normally difficult to incorporate into the structure of the pneumatic tool in a simplified manner.